Refining phenols



' Patented .Oct. l7, 1933 REFINING PBENOLS I Erik Clemmensen and Boy M. Miller, St. Louis,

Mo., assignors, by mesne assignments, to Monsanto Chemical Company, a corpora on of Delaware No Drawing. Application June 29, 163i Serial No. 547,790

4 Claims. (01. 202-57) This invention relates to the refining of cresols or phenols or mixtures thereof such as is ob-v tained, for example, from coal tar distillates,

and it has particular application tola method of. 5 refining crude cresols-and/ or phenol whereby one -is enabled to remove the color imparting properties and thereby obtain a colorless product which-is stable even in the presence of strong light-for relatively long periods of time.

The object of this invention is to provide a method of refining crude phenol of the type described whereby a colorless product capable of resisting discoloration even in the presence of sunlight for relatively long periods of time may be obtained. V

We'have found that by distilling phenol or cresols'in the presence of a small amount of inorganic bases, either at atmospheric or subatmospheric pressure a colorless relatively light 2 stable product may be obtained.

One method of proceedingv consists in adding to cresol before or after the phenol has been separated therefrom and which may consist of one or more of the cresol isomers, approximately 1% by weight of soda ash. A slight evolution of carbon dioxide will generally be observed. After agitating the mixture of cresol and soda-ash for a short time to insure uniformdistribut'ion of the soda ash in. the charge and'complete' reaction with impurities present, the mixture is distilled according to the usual practice. A small amount of residue remains, which consists large- 1y ofunreacted soda ash together with a small amount of the salts of coal tar acid impurities. The product is colorless and does not discolor appreciably-even after several weeks. Without the addition of the soda ash the distilled product retains' a charaeteristicpink or brown coloration even after repeateddistillation and turns a dark 40 red or brown after but a few days.

While we have found that the alkali metal carbonates and bicarbonates are particularly well suited, a variety of inorganic bases may be employ-ed. including the alkaline earth metal carbonates and bicarbonates, as well aaoxid'es or hydroxides, the alkali metal hydroxides or the alkali metal and alkaline earth metal salts of weak acids, such for example as, sodium cresy lates or phenate, which may be obtained by treatin: cresol or phenol withvcaustic soda.

From the foregoing. description, it will be apparent that this invention affords a simple and eiiective means of improving the quality oijphenol and cresols, that it does not necessitate the installation of special equipment, nor does it require the supervision of a skilled technician.

Although a specific embodiment of the invention is set forth and several modifications have been indicated, it will be apparent that the invention is susceptible to numerable modifications 5 and variations without departing from the substance thereof and we desire, therefore, that it .be limited only as indicated in the claims. 1' I What we claim is: r

1. The method of refining crude phenols which 55 consists in distilling the same after adding thereto a relatively small quantity as compared to the quantity of phenol being treated of an inorganic base. 2. The method of refining crude cresols, which consists in distilling the same after adding thereto a relatively small quantity as compared'to the quantity of crude cresol being treated of a material selected from a group consisting of the following: the alkali metal carbonates and hydroxides, the alkaline earth metal carbonates, bicarbon'ates, oxides, hydroxides, the alkali and alkaline earth metal cresylates and the bicarbonates of the alkali and alkaline earth metals.

3. The method of refining cresols, which comso J prises distilling the same after adding thereto 'a relatively small quantity of alkali or alkaline nan: CLEMMENSEN. ROYM. muss- 

